1. in a single-period newsvendor model, if the demand is normally distributed with a mean of 80 and a standard deviation of 10, and the optimal service level is 90%, what is the optimal order quantity? 2. in a single-period newsvendor model, if the demand is normally distributed with a mean of 80 and a standard deviation of 20, and the optimal service level is 90%, what is the optimal order quantity?